Buying or making overupgraded weapons is for the richest players in the game.
Attempting to overupgrade for average players is a gamble , you may get a +10 gladius [3] which you can sell for 50M or end up breaking a +9 Gladius[3] which you could've sold for 20M

Richer players dont care, 20M is a trifle for them , 50M is an item worth showing off in their shop lol.
Besides overupgrading also consumes a lot of time with no promise of fruitful results.